Antifriction bearing



Feb. 4, 1941. l... H. STEIN 2,230,471

ANTIFRICTION BEARING Filed oct'. 15, 1958 ,/a l @i E gig# ja ,25 22.20.211521 yf y rz. l

" @www1 Patented Feb. 4, 1941 UNITED STATI-:sll

AN TIFRICTION BEARING Louis H. Stein, Chicago, Ill., assigner to AetnaBall Bearing Manufacturing Company, Chicago, Ill., a, corporation ofIllinois Application October 13, 1938, Serial No. 234,795

'4 Claims.

My invention relates to antifriction bearings and especially to ballthrust bearings such, for

example, as are employed as clutch release bearings in automobiles.

The present invention is concerned with securlng a better seal betweenthe free race and the shell which it carries.

In this type of thrust bearing the free race and the shell carried by itare generally so arranged that they form an annular grease containingreservoir. Because the free race and shell which outwardly delne thisreservoir are often rotating at very high speeds, the grease issubjected to a very considerable centrifugal pressure which readily ndsa path of leakage forthe grease if the shell be imperfectly sealed tothe free race ring.

The constructions heretofore used in spinning the shell onto the freerace ring, as well as other expedients for sealingly mounting the shellupon the free race, `have not proved satisfactory because ofimperfections in the seal which, under the high centrifugal pressure ofthe grease as explained, cause leakage. By a simple change in thestructure of the parts and the method of their assembly-and withoutperceptibiy increasing the cost of the parts or the cost of theirassembly-I have achieved a mounting of the shell upon the free race ringwith a reliably perfect seal. Observations in extensive production andfield use have shown that my improvement is eminently suited forcommercial production and can be relied upon to provide a perfect sealwhichis not only initially obtained, but maintained` for the life of thebearing.

The maintaining of a seal to prevent leakage of grease from thereservoir within the bearing is important, because in present-dayautomobile practice the clutch release bearings are calculated to runindefinitely without further grease than that with which `they arepacked at the factory.

Y The clutch release bearing is thus one which does not receive routineservice station lubrication to preclude its running dry. If one of theseclutch release bearings leaves the factory with a defective seal betweenthe shell and the free race ring,

or if one subsequently develops due to constantV clutch release bearingof the type shown in my (Cl. 30S-187.1)

Patent No. 1,958,725 of May 15, 1934, but more' especially as shown inmy application Serial No. 175,779 nled Noyember 22, 1937, now Patent No.

2,140,818, of December 20, 1938. The latter application is concernedwith the solution of the problem of leakage in the clearance passagebetween the distant face of the fixedrace ring and the embracing flangeof the shell, whereas the present invention, as stated, is concernedwith the effective elimination of leakage between the. shell and theiixed race ring by which it is carried.

In the drawing:

Fig. 1 is a diagrammatic section of a clutch release mechanism includinga clutch release bearmg incorporating the present invention;

Fig. 2 is a radial section of the clutch release bearing upon anenlarged scale in its assembly position just prior to the operation ofspinning the shell onto the free race; Y

Fig. 3 is a similar radial section after the spinning operation iscompleted; and

Fig. 4 is a. somewhat diagrammatic elevation of apparatus which may beemployed for this spinning operation. 1

In the exemplary clutch release bearing here used to illustrate anapplication of my present invention, the xed race Ill is a drive lit ona sliding or floating hub Il, reciprocably mounted on the stationarytubular support I2, the race ring I abutting a shoulder I3 on thesliding hub II. The sliding hub, it will be understood, is reciprocatedby the conventional clutch pedal through the clutch fork shown.

The outer face of the free race ring I4 is contacted by a plurality ofradially arranged clutch release levers or fingers I5. The race ringsIII and I4 havethe conventional ball race grooves I6 and I 1,respectively. are disposed in transverse openings I9A in the ballretainer ring 20.

Pursuant to the improvement set forth in my Patent N o. 1,958,725, theretainer ring `Ztl carries a hub portion 2|, which has 'a sliding lit on the shaft, the shaft in this instance being the hub II. One end of thehub 2l extends as an annular flange 22 into a counterbore 23'in the xedrace ring I0, the counterbore and the flange 22 providing a running fit.The passage end of the hub extends as a wider annular flange 2l whichhas'a running t in the bore of the free racering I4. Thus, of the threerings I0, I4

and 20, only the xed race ring III has a drive fit on the shaft; theother rings have a running lit relative to each other and to the shaft.The purpose of this arrangement is to enable the The arcuately spacedballs I8' 'retainer ring better to hold the balls in alignment with thegrooves, especially when the thrust load is relieved and subsequentlyre-assumed. Because of the continual slight wear of the re- 5 tainerring against the race rings and shaft, I

prefer to form the retainer ring of a self-lubricating metal as, forexample, the phosphor high lead content bronze or the oil impregnatedporous bearing metal mentioned in my prior patl0 ent.

'I'he component parts are preassembledinto a unit by e. stamp or spunsheet metal jacket or shell 25 embracing the two race rings. The shellhas a deep vertical flange 26 loosely embracing the fixed race ring I0with a normal clearance of some .0Q5" and xedly embracing the free racering i4 to rotate therewith.

The shell 25 comprises a cylindrical portion 30 which is extended at oneend, through an obliquely chamfered corner portion 3|, into an inwardlydirected vertical iiange 32 which lies in a plane at a normal to theaxis and closely over= nes the back :ace of the fixed race ring le.

Toward its other end the cylindrical portion i 30 of the shell extendsthrough a pre-formed offset or shoulder 33 into a. cylindrical rimportion 34 in the form in which the shell is pre-formed.

'I'he enlarged cylindrical ring portion 34, as

shown in Fig. 2, is adapted to receive the rim of the free ra'ce ring I4with` the annular running `edge formed by the intersection of the ballface of the free race ring I4 and its rim lying against lthe shoulder33.

'I'he outer corner of the free race ring i4, re-

35 mote from its ball face, is chamfered at an angle of about 35 or 40degrees to the axis, as indicated at 35, leaving a rim face of about ofthe thickness of the free race ring. Especial attention is directed tothe relative contours of the 40 rim face and the chamfer 35. The.chamfer is not extended obliquely all of the way to the rim face.Instead, there is a vertical cut 36 inwardlyfrom the rim face forming aright-angled annular edge 31. The cut 36 spaces the proximate edge ofthe chamfer from the rim face.

While'the parts are in the relative-position of Fig. 2, and while thefree race ring I4 is braced axially against the shell to hold the nearperipheral edge of the race-ring against the shoulder 33, the initiallycylindrical rim portion 34 of the shell is spun against the rim face ofthe free race ring, and spun down u'pon the chamfer 35 and at the sametime over the edge 31 and against the cut or shoulder 36. i

The peculiar eflicacy of this construction in affording a reliable andperfect seal is attribut- ,l

able largely to the character of the materialy of at least the pertinentportions of the race ring and of the shell. The shell is pre-formed-'byo stamping for examplefrom a relatively soft, low carbon, cold rolledsheet steel. On the other hand, the free-race ring is surfaced with ahigh carbon steel which is virtually of tool steel hardness as theresult of a carbonizing heat treatg5 ment which hardens the surfacesomewhat after the fashion of case hardening, but to a considerablygreater depth, as is indicated by the crosshatchng of the race ring inFigs. 2 and 3.

As a result of the forceful spinning of the 70 relatively soft shellonto the profile of the very hard tool-steel-likerace ring, theinitially cylindrical rim portion of the shell is not merely bent aroundthe proximate prole of the race ring; the salient corners of the racering actually cut 7g into the metal of the shell to provide a morepera,aso,471 I feet sat1. as a rennt o: thslcombmed action ci cuttingand flowing upon the relatively soft metal of the shell, a particularlyeffective' and perfect seal is attained at both salient edges of the rimface of the race ring and. in addition, the shell is tightly pressedagainst the rim face. against the shoulder at the cut, and against thesurface of the chamfer.

In addition to these sealing edges and surfaces, spinning of the metalof the shell, in conjunction with the cutting of its metal and theflowing of its metal, results in an internal contractive strain in themetal of the shell which bridges between the two edges of the rim face,permanently clamping the salient edges of the rim face between the cutsthat have been made into the stock of the shell. This contractive strainis incorporated in the mentioned bridging portion of the shell as theresult of the axial pull upon. the shell stock at that region by thespinning of the end of the shell over the chamfer while at the same timecutting the `salient edge of the rim face into the stock of the shell.

In Fig.'4 I have illustrated somewhat diagrammatically 'a device forperforming this final spinning operation. The bearing, with the parts inthe relation of Fig. 2, is placed upon a table 43 with the free racering uppermost. 'lhe lower end of a depending rotary spinning shaft 4Icarries a thrust bearing 42, the lower or stationary race 43 of which isconformed to enter the bore of the fixed race ring I4 to center thebearing assembly. The spinning head 44 also carried at the lower end ofthe shaft 4| presents a set of three obliquely radial studs 4i, each ofwhich carf ries a spinning roller 46.

Each roller 43 hasa cylindrical portion 41 arranged at substantially theangle of the chamfer 35 and a flange-like surface 4l which comes into lAtangency with the cylindrical portion of the shell opposite the rimface of the race ring. along a vertical line. By moving the rotatinghead 44 downwardly toward Athe table (or, alternatively, moving thetable 4l upwardly), the upper edge of the shell is engaged first by theflangelike portions 43 of the ollers and then directed inwardly alongthe cylindrical portions 41 of the rollers l which spin the initiallycylindrical rim portion of the shell inwardly against the chamfer of therace ring. Axial thrust through the thrust bearing 42 presses the thenlower edge of the race ring into the shoulder 33, cutting itself a moreperfect seat. The flange-like portions '4. of the rollers serve to pressthe shell very tightly against the rim face of the race ring and to thisend the line of tangency of the flange-like por,- tions with the shellmay be slightly out of the vertical to supply-a camming action.

Having thus described and illustrated an exemplary embodiment of myinvention, what I claim is:

l. An antifriction thrust bearing comprising a free race ring, a xedrace ring opposed thereto', antifriction elements rolling between theopposed faces of the rings, the rim face of the free race ring beingannularly sharp-edged at itsnear corner and chamfered at its remotecorner leaving a remote-facing shoulder between the chamfer and theremaining face of the ring with an annular sharp edge where the shoulderand remaining rim face join, and a grease retaining shell iixedlycarried by .the freerace ring, the shell being of sheet metal ofhardness and elasticity in the order of that of a relatively soft, rlowcarbon, cold rolled sheet steel and comprising a cylindrical portionanged inwardly at one tially right-angled sharp edges at the near andend to embrace the remote face of the fixed race remote edges of the rimface, and at its outer ring and adjacent its other end presenting aremote corner being chamfered in the order of shoulder receiving thesaid near sharp edge of forty-ve degrees with a remote-facing shoulderthe free rac'e ring and extending therebeyond between the chamfer andrim face, and a grease over the said remote sharp edge of the free raceretaining shell of sheet metal of hardness and ring and its shoulder andalong the chamfer, the elasticity in the order of that of a relativelysoft, metal of the free race ring which forms its said low carbon, coldrolled sheet steel flxedly caredges being hardened to the order of toolsteel ried by the ring and comprising a generally cyhardness, wherebythe edges cut into the shell lindrical portion embracing the rim faceand to form a cut seal therewith. shouldered to receive the said edgesof the ring 2. An antifriction thrust bearing according to and extendingalong the chamfer in intimate claim 1, in which the radial height of theshoulder contact therewith, the hardened steel of said is in the orderof the thickness of the stock of edges being cut into the soft metal ofthe shell the Shen, to seal the shell to the ring.

3. As a member of an antifriction thrust bear- 4. A bearing memberaccording to claim 3, in ing, a free race ring of hardened steelpresenting which the radial height of the shoulder is in the a rollingface for antifrictlon elements and a order of the thickness of the stockof the shell. narrow rim face presenting annular, substan- LOUIS H.STEIN.

